It was driving me nuts but today I have reduced high pitch noise (2.8khz) by around 7-8db as measured by my phone. The solution was to put mineral wool between drive unit and firewall. Not too elegant solution but can be easily done. If you wan to try it make sure water can still go down from the air filter area down. The amount of wool I used was around 5 square meters in total. I am very pleased with the result. The high pitch is greatly reduced. I can now listen to the music 2 steps lower on the volume. The noise is not completelly gone but its not annoying anymore.
The wool itself is not flammable, is great sound absorber and acts as a protective layer from dirt. The only culprit would be it stops the heat transfer but that should not be a problem as the components are connected through coolant link anyways to transfer the heat to radiators.
I welcome any comments.
Video
The wool itself is not flammable, is great sound absorber and acts as a protective layer from dirt. The only culprit would be it stops the heat transfer but that should not be a problem as the components are connected through coolant link anyways to transfer the heat to radiators.
I welcome any comments.
Video